An anal fistula is an abnormal passage or connection between the anal canal, including the colon, bowel or rectum, and the perianal skin. Contaminants or waste matter, such as excrement or feces, may pass through the fistula tract rather than passing naturally through the anal sphincter to exit the body.
An anal fistula may be treated by cleaning the fistula tract and inserting a seton, which may include a cord with a thread and a penrose drain, to maintain the fistula open for drainage. However, contamination or waste matter may not necessarily exit via the anal sphincter when treating the fistula with a seton.
It has been proposed to close an anal fistula using an anal fistula plug. Such plugs are configured to be fitted into and close the fistula so that contamination or waste matter is directed away from the fistula and naturally exits the body through the anal sphincter.